However, a problem with most, if not all, such connector systems is that a single geodesic dome design can demand not one but a plurality of different connector shapes for construction. The different shapes may include different aximuthal angles or peripheral-angles between arms, different elevational angles between arms and hub, different positioning of arms along the length of the hub, different arm lengths and attachment distances, different arm orientations about arm long axes, and the like. In particular the requirement for differing arm-azimuthal angles is difficult to meet economically and precisely, particularly if the arms are to be in plan view, perpendicular to facets of a tubular polgonal hub. Such hubs are expensive and demanding to make piece by piece and casting systems are too inflexible to permit practical variations of the type required.